Isn’t this common in other countries, where a “notary” has to sign contracts as well?
Normal commercial purchase contracts don't need the added insurance that offers. And no one wants to pay for it.
Having been involved in the negotiation and signing of many, many commercial purchase contracts (primarily in the US), I have never seen one be notarized. This includes at three giant publicly-traded companies and at three venture-funded startups.
Notaries exist to verify identity. If identity verification wasn’t an issue. They might not be necessary.
There are probably other ways of accomplishing the same thing.
Also it's sort of moot, the notary effectively just puts a stamp on it. If I write up a quit claim deed, there exists no mechanism to prove my ownership of that anyways
The exception I dare say are the UK and US.
The legal tradition in the west largely stems from the Roman Iius civile. Even the so called common law. And there too we see a role for civil officers to authenticate real estate transactions.
So... your statement is false